Plug with fuse

ABSTRACT

A housing of electrically insulating material has an internal cavity which communicates via an opening with the exterior. Two or more male or female terminals are carried by the housing, and one of these terminals is directly connected with a conductor a free end of which is connectable with an energy source or a user device. A pair of metallic spring clips are located in the cavity and hold by friction a replaceable fuse which is removable and insertable through the opening. One section of another electric conductor conductively connects the other terminal with one of the spring clips and another section is connected to the other of the spring clips and has a free end connectable with the energy source or the user device. A cover, in form of a separate, hingedly connected or integral member is provided on the housing and normally closes the opening of the cavity. A snap latch holds the cover in place, and the cover is advantageously transparent so that the fuse may be inspected without removing the cover. A construction wherein the &#39;&#39;&#39;&#39;burned out&#39;&#39;&#39;&#39; fuse effects the opening of the cover to provide visual indication of the circuit interruption, and a construction where the same indication is provided but where the fuse is replaced by a bimetallic element, are also disclosed.

United States Patent Charles J. Mineo 39-50-65th Place Woodside Queens, New

[72] Inventor York, NY. 211 AppLNo. 2,562 [22] Filed Jan. 13,1970

45 Patented Jan. 11,1972

[54] PLUG WITH FUSE 10 Claims, 6 Drawing Figs.

[52] u.s.c| 337/206,

337/197,337/244,337/265,337/l47P 51 lnt.Cl ..l-l0lh85/30 [50] FieldofSearch 339/14,

Primary Examiner-Marvin A. Champion Assistant Examiner-Robert A. Hafer AttorneySaul Jecies ABSTRACT: A housing of electrically insulating material has an internal cavity which communicates via an opening with the exterior. Two or more male or female terminals are carried by the housing, and one of these terminals is directly connected with a conductor a free end of which is connectable with an energy source or a user device. A pair of metallic spring clips are located in the cavity and hold by friction a replaceable fuse which is removable and insertable through the opening. One section of another electric conductor conductively connects the other terminal with one of the spring clips and another section is connected to the other of the spring clips and has a free end connectable with the energy source or the user device. A cover, in form ofa separate, hingedly connected or integral member is provided on the housing and normally closes the opening ofthe cavity. A snap latch holds the cover in place, and the cover is advantageously transparent so that the fuse may be inspected without removing the cover.

A construction wherein the burned out" fuse effects the opening of the cover to provide visual indication of the circuit interruption, and a construction where the same indication is provided but where the fuse is replaced by a bimetallic element, are also disclosed.

The present invention relates generally to electrical connectors, and more particularly to fused electrical plugs.

Fused electrical plugs per se are already known. However, the prior art constructions of which I have become aware are possessed of certain disadvantages which render them impractical-if not actually unsafe-for use by persons devoid of electrical skills andknowledge. Specifically, in these constructions the insertion and/or extraction of the fuse may require tools, it may be possible only upon disassembling the plug, it may carry with it a shock hazard if done carelessly or by an unskilled person, the identification of a burned-out fuse may be difficult, or a combination of these and other problems may be present.

A truly foolproof fused plug, which can be readily and safely used and serviced even by persons of no electrical knowledge or skills, has not yet become known.

SUMMARY OF THE INVENTION It is, accordingly, an object of the invention to provide a thus improved fused electrical plug.

More particularly, it is an object of the invention to provide a fused electrical plug which is simple in construction, inexpensive, and safe to use and to service.

In pursuance of these objects, and others which will become apparent hereafter, one embodiment of my novel fused electric plug comprises, briefly stated, a housing of electrically insulating material which is provided with an internal cavity hav ing an opening communicating with the exterior of the housing. A removable cover normally closes this opening.

Fuse holder clips are mounted in the cavity and hold a replaceable electric fuse which can be inserted and removed from the clips through the opening upon removal of the cover.

At least two electric terminals of male or female type are provided and connected in fused circuit with the replaceable fuse.

This construction, in which the cover is advantageously transparent, provides for ready inspection of the fuse to determine its operative state, and for removal and replacement of a burned-out fuse without necessity for disassembling the plug or gaining access to any current-carrying components thereof.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and mode of operation, together with additional objects and advantages, will be best understood from the following description of specific embodiments when read in conjunction with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a somewhat diagrammatic perspective view of one embodiment;

FIG. 2 is an exploded perspective showing a detail of FIG. 1;

FIG. 3 is a plan view of a further embodiment;

FIG. 4 is still another embodiment shown in a view similar to FIG. 1;

FIG. 5 is a diagrammatic detail of yet another embodiment of the invention; and

FIG. 6 is a view similar to FIG. 5, but illustrating still an additional embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing the drawing now in detail, and firstly FIG. I, it will be seen that reference numeral 1 generally identifies the novel plug. The term plug as employed herein is intended to refer to both to male and female connectors of any type which can be fused in accordance with the present invention.

Plug 1 has a housing 2 of electrically insulating material, e.g., rubber, synthetic plastic or the like. In FIG. 1 this housing 2 is so 'configurated as to define a step 3 and the outer wall of ARA! the housing is provided with an opening 4 which communicates with an interior cavity (not numbered).

According to the invention, the opening 4 can be closed by a cover 5 which may be advantageously transparent. Cover 5 may be a separate member, as it may be hingedly connected to the housing 2. In FIG. 1 the cover 5 consists of the same material as housing 2 and is connected thereto by a thin integral strap, which latter thus constitutes an integral hinge. Plastics are known which permit large numbers of flexing motions without breakage and which are therefore especially well suited for such integral hinge" applications.

To keep cover 5 normally in a position closing opening 4, a

latch is provided which in FIG. 1 is identified as a snap latch 6.

This may simply be a flexible portion of cover 5 which snaps over a bead, rim, edge, projection or the. like on the housing 2, slight pull exerted by the fingers of a user being sutficient to open the cover 5.

Located in the aforementioned cavity are two fuse holders 8 (see also FIG. 2) which may be mounted on a common base strip 8a of insulating material. In FIGS. 1 and 2the fuse holders 8 are metallic spring clips between whose opposed arms a fuse 9 may be removably inserted. The fuse 9 has a nonconductive portion 9b at whose opposite ends are located conductive caps 9a, with a fusible wire 9c connecting the caps 9a internally in conventional manner. When inserted into the clips 8, the caps 9a make electrical contact with the same and complete via wire 9c the circuit between the two clips 8.

Plug 1 is further provided with a pair of conventional contacts 7, in this instance male contacts which are matingly insertable in cooperating female contacts in known manner. The showing of contacts 7 is diagrammatic and they will of course be constructed and configurated in conventional manner and as required by applicable codes or standards.

Reference numeral 10 identifies one electric conductor connected to one of the contacts 7 and having a free end which may in conventional manner be connected to a user device as to a source of electric energy, depending upon the type of plug involved. In FIG. I the connection will normally be to electric user device. The other terminal 7 is connected to one of the spring clips 8and thus to fuse 9via a conductor section 11b, while the other spring clip 8 is connected with a section lla which has a free end for connection to a user device or source of electrical energy (as the case may be) together with the free end of conductor 10.

If the fuse 9 burns out" for any reason, the cover 5 is opened, the fuse extracted and a new fuse put in place, all without requiring electrical skill or knowledge and with perfeet safety. If the fuse is of the type which provides a clear external showing of burnout, e.g., if the portion 9b is of glass or plastic so that wire 9c may be seen to be melted, the cover 5 may be of transparent material so that the fuse 9 can be inspected without opening the cover.

The embodiment of FIG. 3 differs from that of FIG. 1 in that the plug la is of differentand more conventional-shape. Like reference numerals identify like components. The housing is here designated 2a and the contacts are identified with 1 reference numeral 7a because they are female contacts of conventional construction. The cavity accommodating the fuse and fuse holders has reference numeral 12. Cover 5a here is a detached member provided at opposite sides with two of the snap latches 6.

The embodiment of FIG. 4 is analogous to that of FIG. 1, except that it is illustrative of the invention incorporated in a grounded plug. Again, like reference numerals identify like components. Additionally, however, this embodiment is provided with a grounding contact 13 which, in conventional manner, is of somewhat different cross section than the contacts 7, so as to be keyed to its own female counterpart in a plug or socket with which the plug of FIG. 4 mates. Grounding contact 13 is conductively connected to grounding wire 14 in known manner. Otherwise, FIG. 4 resembles FIG. 1.

FIG. 5 shows that, according to a further concept of the invention, the novel plug may also be constructed in such a manner that occurrence of an overload with concomitant burning out of the fuse trips the latch on cover 5 (not shown) to provide a visual indication that a new fuse must be installed.

Reference numeral identifies the fuse which is of the replaceable type described before. The fuse-holding spring clips 16 also correspond to those previously described. Reference numeral 17, however, identifies a member which is pivotable about the pivot axis 18-for instance a pin passing through the member 17 and mounted in the plug housingand which cooperates with the abutments 19, 19a. The expansion spring 22 acts between the housing and the member 17, urging the latter to the illustrated position in which the (in the drawing) right-hand end of member 17 abuts against abutment 19a.

A bimetallic element 20 of known construction is mounted in the housing and extends freely through the right-hand fuseholding clip 16 below the fuse 15; its free end portion is located beneath the member 17. The electrical conductors are identified with reference numeral 21 and their connections to the one clip 19 and the bimetallic element 20, respectively, with reference numeral 21a.

Element 20 extends through the right-hand clip 16 in such a manner as not to be prevented from movement relative thereto, but to be in conductive contact therewith so as to complete the circuit to fuse 15. If an overload occurs and the fuse l5 burns out," the heating of the element 20 causes the free end thereof to move upwardly, pushing the fuse 15 out of the right-hand clip 16 and, with the latch on cover 5 (not shown but readily understandable) being so located that the fuse will press thereagainst, the cover 5 is thereby caused to open and indicate the need for replacement of the fuse.

The embodiment of FIG. 5 could be modified by omitting member 17, its abutments 19, 19a and the spring 22, and having the bimetallic element 20 act directly upon the fuse 15.

Finally, FIG. 6 shows that the novel plug may also be constructed in a manner analogous to a circuit breaker. The fuse v is here replaced with a bimetallic element 23 which is mounted in the housing via a screw 24. The latter also connects the element 23 with the AC conductor 25. A second AC conductor 26 is connected to a contact 27, as shown, with which the free end of element 23 is in conductive engagement when the circuit is closed, i.e., in normal operating condition.

An insulating member 28 is pivotably mounted at 29 for turning movement about an axis normal to the plane of the drawing. An expansion spring 30 acts between the member 28 and the housing, urging the member 28 to the illustrated position. Evidently, a contraction spring could be used if it were to act from the opposite side.

An overload in the circuit causes the bimetallic element 23 to bend upwardly in FIG. 6, whereby the tip 23a of the free end of element 23 deflects element 28 to the right until the tip has cleared the element 28, whereupon the latter returns to the illustrated position. This requires, of course, a suitable nonillustrated abutment to prevent member 28 from moving to the left beyond the illustrated position. The tip 23a now rests on the inclined upper edge face 280 of member 28 and the circuit is interrupted. The force exerted by subsequent straightening of element 23, in response to cooling, is insufficient to deflect member 28 in a sense permitting element 23 to return to its circuit completing position which is shown in FIG. 6.

According to the invention the cover 5 or latch thereof is so located with reference to the tip 23a that upward movement of the latter to circuit interrupting position causes the cover 5 to open, thereby providing a visual indication that the circuit is interrupted. To restore the device to operative conditionafter the cause of the short circuit has been detected and correctedpressure is exerted on the cover 5, and thereby on the tip 23a. This causes tip 23a to slide upon the edge face 28a, deflecting the member 28 towards the right so that the element 23 may again move into engagement with contact 27, thereby restoring the circuit to operative position.

It will be understood that the elements described above may also find a useful application in other constructions differing from those described above.

While the invention has been illustrated and described as embodied in a fused plug, it is not intended to be limited to the details shown, because various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

The foregoing will so fully reveal the gist of the present invention that others can readily adapt it for various applications and, therefore, such adaptations are intended to be comprehended within the meaning and range of equivalence of the following claims.

While an electrical plug is illustrated, the invention can also be applied to other electrical connectors.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

What is claimed is:

1. A fused electrical connector, such as a plug, comprising a housing of electrically insulating material and provided with an internal cavity having an opening communicating with the exterior of said housing; cover means connected with said housing and displaceable between a first and a second position in which it completely closes and at least partly exposes said opening, respectively; fuse holder means mounted in said cavity; a replaceable fuse in electrically conductive engagement with said fuse holder means and positioned proximal to said opening and said cover means; at least a pair of electric terminals at least partly accommodated in said housing; first conductor means conductively connected with one of said electric terminals and having a free end; second conductor means including a first section conductively connecting the other of said terminals with said fuse holder means, and a second section conductively connected with said other terminal and also having a free end; and actuating means in circuit with said fuse and operative for at least partially displacing said fuse with reference to said fuse holder means in response to occurrence of an overload and burnout of said fuse, and in a sense effecting displacement of said cover means from said first to said second position thereof so that the cover means provides a visual indication of the operative state of said plug.

2. A fused electrical connector, such as a plug, comprising a housing of electrically insulating material and provided with an internal cavity having an opening communicating with the exterior of said housing; cover means connected with said housing and displaceable between a first and a second position in which it completely closes and at least partly exposes said opening, respectively; at least a pair of electric terminals at least partly accommodated in said housing; and electric fuse means in said cavity proximal to said cover means in circuit with one of said terminals and displaceable in response to occurrence of a current overload between an operative position in which it is in circuit with the other of said terminals, and an inoperative position in which it is electrically disconnected from said other terminal and displaced with reference to said operative position in a sense engaging said cover means and effecting displacement of the latter to said second position thereof.

3. A fused electrical connector as defined in claim 2 wherein said cover means is discrete from said housing.

4. A fused electrical connector as defined in claim 2, wherein said housing and said cover means are composed at least predominantly of synthetic plastic material.

5. A fused electrical connector as defined in claim 2, wherein said terminals are projecting blades each comprising a portion projecting from said housing for insertion into a mating receptacle.

6. A fused electrical connector as defined in claim 2, wherein said terminals are female sockets each having an open end for insertion of a mating male terminal, said housing having respective apertures each communicating with one of said open ends.

9. A fused electrical connector as defined in claim 2 and further comprising releasable latch means for normally maintaining said cover means in said first position thereof.

10. A fused electrical connector as defined in claim 2; and further comprising fuse holder means in said housing and comprising a pair of spaced electrically conductive clips each adapted to engage said fuse means and each being conductively connected with one of said electric terminals. 

1. A fused electrical connector, such as a plug, comprising a housing of electrically insulating material and provided with an internal cavity having an opening communicating with the exterior of said housing; cover means connected with said housing and displaceable between a first and a second position in which it completely closes and at least partly exposes said opening, respectively; fuse holder means mounted in said cavity; a replaceable fuse in electrically conductive engagement with said fuse holder means and positioned proximal to said opening and said cover means; at least a pair of electric terminals at least partly accommodated in said housing; first conductor means conductively connected with one of said electric terminals and having a free end; second conductor means including a first section conductively connecting the other of said terminals with said fuse holder means, and a second section conductively connected with said other terminal and also having a free end; and actuating means in circuit with said fuse and operative for at least partially displacing said fuse with reference to said fuse holder means in response to occurrence of an overload and burnout of said fuse, and in a sense effecting displacement of said cover means from said first to said second position thereof so that the cover means provides a visual indication of the operative state of said plug.
 2. A fused electrical connector, such as a plug, comprising a housing of electrically insulating material and provided with an internal cavity having an opening communicating with the exterior of said housing; cover means connected with said housing and displaceable between a first and a second position in which it completely closes and at least partly exposes said opening, respectively; at least a pair of electric terminals at least partly accommodated in said housing; and electric fuse means in said cavity proximal to said cover means in circuit with one of said terminals and displaceable in response to occurrence of a current overload between an operative position in which it is in circuit with the other of said terminals, and an inoperative position in which it is electrically disconnected from said other terminal and displaced with reference to said operative position in a sense engaging said cover means and effecting displacement of the latter to said second position thereof.
 3. A fused electrical connector as defined in claim 2 wherein said cover means is discrete from said housing.
 4. A fused electrical connector as defined in claim 2, wherein said housing and said cover means are composed at least predominantly of synthetic plastic material.
 5. A fused electrical connector as defined in claim 2, wherein said terminals are projecting blades each comprising a portion projecting from said housing for insertion into a mating receptacle.
 6. A fused electrical connector as defined in claim 2, wherein said terminals are female sockets each having an open end for insertion of a mating male terminal, said housing having respective apertures each communicating with one of said open ends.
 7. A fused electrical connector as defined in claim 2, and further comprising an additional electric terminal also at least in part accommodated in said housing, and neutral third conductor means conductively connected with said additional electric terminal and having a free end.
 8. A fused electrical connector as defined in claim 2, wherein said cover means consists at least in part of transparent material for enabling visual observation therethrough of the operational condition of said fuse.
 9. A fused electrical connector as defined in claim 2 and further comprising releasable latch means for normally maintaining said cover means in said first position thereof.
 10. A fused electrical connector as defined in claim 2; and further comprising fuse holder means in said housing and comprising a pair of spaced electrically conductive clips each adapted to engage said fuse means and each being conductively connected with one of said electric terminals. 